Uninstalling Quicktime,installing iTunes 7.0 ... Easy

Step 1.Download Windows Install Cleanup utility from here

Step 2.Uninstall Quicktime,iTunes(if already installed)
Cleanup the temp folder if u tried multiple times to install iTunes

Step 3.Delete quicktime folder from here
\Program Files\QuickTime
\Documents and Settings\All Users\Application Data\Apple Computer\QuickTime

Step 4.Download some Registry cleaner..i prefer Registry Mechanic ..Run it ..make sure it deletes all the unwanted registry keys

Done ..Reboot the computer ..and now U r ready to install the iTunes 7.0

tried and tested ..Works fine..If u still hav some problem feel free to comment